The invention relates to a worm-like mechanism, in particular a worm-type or serpentine deformable handling mechanism.
Worm-like or serpentine mechanisms, for example for endoscopy, that consist of a continuously deformable carrier, are known. Provided perpendicularly at specific spacings on this carrier are disks with fastening points that are connected to the ends of wire ropes that are carried along on the carrier. If one or more of these wire ropes is tensioned, this leads to a curvature of the mechanism.
DE 198 33 340 A1 further discloses a worm-like working mechanism that has as central supporting element a stretch-elastic restoring device on which disk-shaped supporting elements are fitted perpendicularly at specific spacings. Provided around the central stretch-elastic restoring device are three actuators that respectively consist of a row of pockets or pads lying one against another. The individual pockets or pads respectively lie in this case between two supporting elements. A liquid or gaseous pressure medium can be fed to each of these actuators via a dedicated access channel such that the pads of the actuators occupy different volumes depending on the filling state. The pads press one another apart. If pressure medium is applied uniformly to the three actuators, the result is a change in the length of the working mechanism. If pressure medium is applied differentially to the three actuators, this produces a corresponding curvature of the working mechanism. Individually or in groups, the pads are hereby respectively equipped with a dedicated feed for the pressure medium.
U.S. Pat. No. 3,284,964 discloses a serpentine, flexible gripper arm structure that has three sections each having a multiplicity of actuating units. The feeding of a working medium to an actuating unit or group of actuating units that respectively consist of pads or bellows arranged between supporting elements is performed starting from a central unit at which the control of the working pressure is undertaken for each actuating unit or group of actuating units. This central unit is located outside the flexible gripper arm structure and is normally large and heavy. Above all, however, this design results in large line lengths, the consequence of the dead times resulting therefrom being a poor capability for open-looped or closed-loop control of the mechanism. Moreover, the base of the gripper arm, through which all the lines are guided, has a large circumference that grows with the length of the gripper arm and/or the number of segments. The result of this is that such mechanisms normally become very thick in relation to their length, and so their mobility is substantially restricted.
Instead of using pressure pads or bellows that expand upon pressure application and effect a lengthening, it is also possible to use so-called artificial muscles such as are available from Festo AG & Co. KG, Esslingen, Germany.
It is the object of the invention to provide a further worm-like mechanism whose movements can be subjected to precise open-loop or closed-loop control in conjunction, in particular, with a simplified, slim design.
This object is achieved by the worm-like mechanism as claimed in claim 1. Advantageous refinements and developments of the invention are described in the subclaims.